Double bowl scraper



Feb. 14, 1939. P. A. BACKMAN DOUBLE BOWL SCRAPER 3 Sheets-Sheet 1 Filed March 22, 1937 INVENTOR fiABackman Feb. 14, 1939;

P. A. BACKMAN DOUBLE BOWL SCRAPER 3 Sheet-Sheet 2 Filed March 22, 1957 v INVENTOR fl/lfiackman Ann-mil Feb. 14, 1939.

P. A. BACKMAN DOUBLE BOWL SCRAPER Filed March 22, 1937 3 Sheets-Sheet 3 Fwlgl l 23 Y r 20 o o 27 l 9 23 7' 32 '8 31a L HI 1 l 'l I I fi L I INVENTOR PAflac/mzan ATTORNEY Patented Feb. 14, 1939 PATENT OFFKIE DOUBLE BOWL SCRAPER Pete A. Backman, Turlock, Calif., assignor of one-third to Klas E. Dahlgren Application March 22, 1937, Serial No. 132,253

6 Claims.

This invention relates to scrapers of the carrying and leveling type and particularly to one of large capacity intended to be drawn by a tractor. My improved scraper includes a pair of longitudinally spaced and separately controlled bowls, the use of which greatly lessens the strains on the tractor while scraping and loading, while enabling the apparatus to have a total capacity equal to that of a scraper of the large single bowl type.

In connection with a scraper of this type it is one object of my invention to mount a leveler blade behind the rear bowl, and to provide a connecting means between the blade and said ll bowl arranged so that the blade will automatically drop to a leveling position with the movement of the bowl to a dumping position, and will be raised to an inoperative position with the movement of the bowl to a loading or carrying 20 position.

Another object of my invention is to provide a front endgate for each bowl arranged to be held in an inoperative position while the bowl is scraping, and to automatically drop to meet the front :45 bowl when the latter is lifted from a scraping position but before the bowl reaches a carrying position. In this manner a minimum of dirt is spilled with the movement of the bowl out of the ground and up to said carrying position. The

30 apron is also arranged so that when the bowl is further swung up to a dumping position, the apron remains in the position occupied when the bowl is in a carrying position, out of the way of dumping operations and of the subsequent re- 5 turn movements of the bowl to a scraping position. A simple and efficient mounting and control means for the bowls is also provided.

These objects I accomplish by means of such structure and relative arrangement of parts as 40 will fully appear by a perusal of the following specification and claims.

In the drawings similar characters of reference indicate corresponding parts in the several views:

Figure 1 is a side elevation of my improved scraper showing the front bowl in a carrying and the rear bowl in a dumping position.

Figure 2 is an enlarged sectional elevation of the rear bowl and cooperating parts in a scraping position.

.30 Figure 3 is a top plan view of the front bowl portion of the scraper.

Referring now more particularly to the characters of reference on the drawings, the scraper comprises spaced side frames each including up- 5., per and lower beams l and 2 respectively, suitably braced and connected to form a rigid structure; the upper beams of the two frames being connected at intervals by cross beams 3. The frame in the front is supported on a swivel wheel truck 4 of suitable form and at the rear end by 6 side wheels 5.

Mounted between the side 'frames are the front and rear bowls 6, each of identical form, size and mounting. Each bowl is pivotally connected to side tension link bars 1 which extend forwardly and down from points on the sides of the bowl near the back and top to pivotal connections with the frame structure ahead of the bowl. The bowl is also pivotally connected to compression link bars 8 which extend rearwardly from points on the sides of the bowl near the bottom and front to pivotal connections with the frame structure rearwardly of the bowl.

The bowl is swung about the bars by a pull cable 9. This extends from a connection with the bottom of the bowl near the back, up over a pulley l0 mounted on an arch frame H extending between the top beams of the side frames, and thence to the structure over a guide pulley l2 mounted on a post l3 upstanding from the frame structure axially of the truck 4. In connection with this cable control arrangement it is to be understood that while I show a single run cable, in practice I preferably use multiple sheave blocks and a corresponding number of runs of the cable to increase the leverage and reduce the strains on the cable and the hoist mechanism connected thereto.

. By this mounting and control of each bowl, the tension or pull on the cable determines the position of the bowl. When the bowl is disposed in a carrying position a predetermined distance clear of the ground, its bottom is horizontal; and when lowered from said position the change of position of the bars I and 8 causes the bottom of the bowl to assume a slight upward slope to the rear, so that the blade I of the bowl enters the ground with a minimum drag behind. As the cable is pulled to raise the bowl above a carrying position, the relative change of position of the mounting bars I and 8 causes the bowl to assume a sharp tilt with the bottom of the bowl at a steep downward angle, thus effecting a rapid and complete discharge of the load from the bowl.

In connection with the rear bowl only I provide a leveler blade l5. This is rigid with rearwardly projecting supporting arms l6 which are disposed between the rear wheels 5 and are pivoted on the frame at its rear end. A cable I! on each side of the scraper is connected at one end on the adiacent-bar 8 intermediate its ends, passes thence upwardly over a pulley I. hung from the frame, and then down to a connection with the blade ii at the top. As the bar 8 is lowered the blade I5 is raised as will be evident; the length of the cable being such that when the bar is at its highest point and the bowl is in a full dumping position, the blade will be lowered to a suitable leveling position. It is here to be noted that the cable connection at either end may be adjusted so as to alter the total operating length of the cable, and thus cause the corresponding position of the blade relative to the bowl to be altered. When the bowl and bar 8 are lowered, the blade is raised so that it is out of the way during scraping operations. In operating the scraper the rear bowl, dumped first, the said bowl being left in its dumping position (if leveling is desired) while the front bowl is subsequently dumped.

Each bowl cooperates with a substantially vertical front gate I! having side walls 20 to overlap the sides of the bowl inwardly thereof. The end gates are rigid with side cross heads 2| slidable in guideways 22 formed in vertical members 23 extending between the top and "bottom frame beams I and 2 at the head of the bowls. Rigid with each .endgate centrally of its width and extending upwardly past and in guided relation with the adjacent cross beam 3 at the front of the same is a post 24 having downwardly facing ratchet teeth 25 on its rear side. A horizontal spring pressed latch dog 26 is slidably mounted on the cross beam 3 to engage any tooth, and when so engaged the endgate is relatively raised or at a level such that if the bottom of the endgate engages the bowl at the scraping blade I, said bowl is then in a carrying position.

The latch is connected to an operating arm 21 which projects radially from a transverse shaft 28 extending to one side of the scraper. Here it is connected to another upwardly projecting radial arm 29 which is connected by a cable III or the like with the substantially vertical ,leg 3| of a bellcrank pivoted on the frame rearwardly of and to one side of the corresponding bowl. The forwardly projecting leg 3 la of the bellcrank extends into the path of a lug 32 projecting from the bowladjacent the top; said lug being under the leg 3la when the bowl is in a scraping position as shown in the dotted position of the rear bowl in Fig. 1.

When the bowl is raised from a scraping position therefore the lug 32 engages the leg Ma and swings the bellcrank, pulling on the cable 30. This rotates the shaft-28 causing the latch to be withdrawn from the teeth of post 24. The latter being thus released, both it and the gate to which it is attached drop of their own weight to meet and engage the upwardly moving bowl before the latter reaches a carrying position. As the bowl continues to rise to such position, the endgate is lifted also until the latch again re-engages a post tooth and prevents the drop of the gate. If rocks or the like adjacent the blade l4 prevent the full downward movement of the endgate to position on said blade, no harm is done since the endgate lifts with the bowl in any event and the latch merely engages another tooth of the post.

When the bowl is again lowered after the lug 32 has once tripped the bellcrank leg Ila and moved above the same, the lug again engages and depresses the bellcrank. In this case the bellcrank is merely deflected without disturbing the latch, on account of the use of the flexible cable 30 which connects the bellcrank with the latch mechanism.

The structure, with a single scraping and leveling unit only, may be used for levee building, surfacing and similar work, in which case a carrying bowl is not used, but only one with a blade and sides, mounted however with the link bar arrangement as described.

It may also be noted that while I have shown the rear bowl in Fig. 1 in an extreme dumping position, satisfactory discharge of the load may usually be accomplished with a lesser degree of elevation of the bowl.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such' detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described my invention, what I claim as new and useful and desire to secure by Letters Patent is:

1. A scraper comprising a wheel supported frame which includes spaced side members, a bowl disposed between the members, compression bars pivoted at their forward end on the bowl adjacent its front and bottom and extending rearwardly to pivotal connections with the frame members rearwardly of the bowl, tension bars pivoted at their rear end on the bowl adjacent the top and back thereof and extending forwardly to pivotal connections with the frame members ahead of the bowl, and a pull element extending upwardly from the back of the bowl on the outside and secured thereon adjacent the bottom of said bowl.

2. A scraper including a wheel supported frame, a bowl in the frame, means mounting the bowl for forward tilting movement from a scraping to a dumping position, means to thus tilt the bowl, a leveler blade separate from and behind the bowl, means mounting the blade on the frame for substantially vertical movement, and connecting means between "the blade and the bowl mounting means arranged to cause the blade to assume a lowered operating position when the bowl is in a dumping position, and to be raised from said operating position when the bowl is lowered to a scraping position.

3. A structure as in claim 2 in which the bowl mounting means includes side bars extending lengthwise of the scraper and pivoted at their opposite ends on the bowl and on the frame rearwardly thereof, and said connecting means comprises pulleys mounted on theframe above the bowl adjacent the back and sides thereof, and cables about and depending from said pulleys; each cable being secured at one end on the corresponding side bar and at the other end on the blade.

4. A scraper including a frame, a bowl therein, means mounting the bowl for upward movement at its front end from a scraping to a carrying position, means to thus move the bowl; a gravity controlled front gate to cooperate with the bowl mounted in the frame for vertical movement, means releasably holding the gate from dropping from the level at which it cooperates with the how] when the latter is in a carrying position, release means for the holding means including an element movable in one direction to effect the release and another element on the bowl positioned to engage and thus move the first named element with the upward movement of the bowl from a scraping position and before it reaches a carrying position.

5. A scrape; including a frame, a bowl therein, means mounting the bowl for upward movement at its front end from a scraping to a carrying position, means to thus move the bowl; a gravity controlled front gate to cooperate with the bowl mounted in the frame for vertical movement, automatically engaging releasable catch means preventing the gate from dropping when raised with the bowl to a level approximately that of the bowl when in carrying position, release means for the catch means including a substantially horizontal arm extending lengthwise of the bowl in a lateral plane outwardly of and adjacent one side of the bowl, and whose upward movement effects the release of the catch means, and 9. lug projecting from said side of the bowl and disposed under the arm when the bowl is in a scraping position at a point on the bowl such as to engage and move the arm up with the upward movement of the bowl from said scraping position and before it reaches a carrying position.

6. A scraper comprising. a wheel supported frame, a bowl disposed in the frame intermediate its ends, compression bars pivoted at their forward end on the sides of the bowl near the front and bottom and extending rearwardly to pivotal connections with the frame only rearwardly of the bowl, tension bars pivoted at their rear end on the sides of the bowl above the pivotal connection of the compression bars therewith and extending forwardly to pivotal connection with the frame, and a pull element extending upwardly from the bowl and connected thereto at a point such as to pull the rear end of the bowl upwardly. i

' PETE A. BACKMAN. 

